But as well-read as they may be, librarians aren't equipped to offer serious health advice or care. Adding to this troublesome trend is the fact that most of the people seeking medical help at libraries are homeless or mentally ill and in need of more care than the average person.

Instead of making the people go to the doctor, though, public libraries in Philadelphia and a small number of other places are bringing health services directly to their patrons.

Last year, a branch of the Philadelphia Free Library was transformed into the South Philadelphia Community Health and Literacy Center. The building has not only a traditional library but also a pediatric and primary care clinic on the top floors.

All of the city's library branches, however, offer some programming to help people get healthier. Seniors can get help enrolling in Medicare; immigrants can take cooking classes; and low-income patrons can learn how to budget for healthy eating -- just to name a few examples. All in all, a whopping half a million residents attended these health-related programs in 2015, according to a study recently published in Health Affairs.

“It’s really good to be given resources to help where we can, especially with referrals, because after all, we’re not social workers,” said Pokorny.

In Queens, N.Y., people can pick up books and attend health-care programs in eight libraries in neighborhoods where doctors are sparse.In Pima County, Ariz., the library system teamed up with the county health department to have one full-time nurse on the library staff and have nurses make rounds in the 27 branches.

One of Pima County's goals of employing nurses was to reduce the number of 911 calls that librarians made because of behavioral issues. Since then, one nurse told Nurse.com that he sometimes sees about 30 people per day who previously might have gotten 911 called on them.

As the U.S. health-care system inches toward one that focuses on population health, libraries aren't the only unexpected partners. Last year, New Orleans trained barbers and hair stylists to help their customers sign up for health care. The Ohio city of Columbus sent health workers to religious temples to talk about getting insured. Fire departments have started integrating data from local health departments to identify frequent 911 users.

But despite the fact that libraries have long been a resource for health needs, the idea that they can be true partners in health care is still foreign to many.

"Many libraries haven’t been exposed to these ideas yet," said Anna Morgan, a lead researcher on the Health Affairs study and a Robert Wood Johnson scholar, "and training courses haven’t necessarily been developed for them."

As the Trump administration lets states experiment with work requirements and other eligibility rules, the costs are adding up. Some policy experts worry they are "shifting spending from health care for needy families to administrative bureaucracy."